Digital Video Broadcasting

Digital Video Broadcasting

1. CAM

2. Protection against the cost infrastruture

3. Content Purchasing

4. Issues

   • constantly streaming content (key syncing)
   • no control who receives content
   • no return path (one way)
   • key distabution

5. Pros of digital

   • Compression
     • 1 analogue = 6 digital
     • MPEG Compression
       • Elementary streams
         • Grouped into Transport Streams
   • allows use of digital crypt

6. Packetised Data

   • 188 Byte Packets
   • PID - Packet ID

7. Protection

   • CSA: Common Scrambling Algorithm
     • DVB Consortium
     • Stream and Block cipher
     • Common Key (CK)
       • 64 bit
       • Changes at least every 20s
     • Block Cipher First
       • Cipher block chaining (8 byte blocks)
       • Stream cipher
         • NLF Cipher
     • Odd / Even Key
     • CW Control Word
       • Sent with every broadcast
       • ECM Message
         • Custom Encrypt
         • Access Requirements
           • checked before CW is decoded
         • Regional Blocks

8. EMM - Entitle Management Message

   • Adds Rights to receiver
   • new subscriptions
   • pay per view
   • K0 deiphher ECM
   • Encrypted with K1
     • long term

9. kn

   • unique to each reciever

10. DVB standards

    • ETSI ETR 289
      • CSA Spec
    • CENELEC 50221
      • common interface
    • ETSI TS 103 197
      • Simulcrypt